The PDF format needs random access, there's no way around. Your best option is
to write the revision to a file and process it from there using the PdfReader
constructor with the RandomAccessFileOrArray as a parameter.
Paulo
> -----Original Message-----
> From: Adriano Santoni [mailto:[email protected]]
> Sent: Tuesday, September 15, 2009 10:07 AM
> To: [email protected]
> Subject: [iText-questions] Memory problems when signing revisions
>
> Hello,
>
> I am not sure whether this question has been posted before; I
> have done some search in the mailing lists archives but found
> nothing...
>
> We have big problems when applying more than one digital
> signatures to a moderately large PDF document (say, more than
> a few MB). Starting from the second one, each subsequent
> signature is done over a revision, which can only be obtained
> as an InputStream.
>
> Unfortunately, when a PdfReader is instantiated from an
> InputStream it reads it all in memory (we have checked this
> in the sources, to be sure), consuming huge amounts of
> virtual memory (especially when the document is a highly
> structured one), which eventually causes the application (and
> the PC) to hang.
>
> Sadly, a RandomAccessFile - which I know to be the only
> efficient alternative - cannot be costructed from an
> InputStream; so a RandomAccessFile can only be used when
> doing the first (top level) signature, but not when the
> subsequent signatures are to be applied, because they are
> applied to revisions...
>
> Is there a way to avoid such a severe memory problem when
> signing a revision?
>
> TIA to all volunteers,
> defacto
>
>
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